Manual operator and lock means therefor for overload protective device



R. W. THOMAS ET AL MANUAL OPERATOR AND LOCK MEANS THEREFOR FOR OVE3,382,336 RLOAD May 7, 1968 PROTECTIVE DEVICE 7 Sheets-Sheet 1 OriginalFiled Aug. 20, 1965 INVENTORS Aaeeer 4 73 0A: Alli/000 Z'x'lflf! May 7,1968 MANUAL OPERATOR Original Filed Aug. 20, 1965 R. W. THOMAS ET AL NDLOCK MEANS THEREFOR FOR OVE PRQTECTIVE DEVICE RLOAD 7 Sheets-Sheet 2INVENTOR.

BY Elk/400 Z F447? May 7, 1968 R. w. THOMAS ET AL 3,382,336

MANUAL OPERATOR AND LOCK MEANS THEREFOR FOR OVERLOAD PROTECTIVE DEVICEOriginal Filed Aug. 20, 1965 7 Sheets-Sheet 5 adv-J INVENTORJ ,1 BY 2M440 2' F147! flrzeaz 5AM, 576:4 651:3 ifjpf'zv May 7, 1968 R. w. THOMASET AL 3,382,336

MANUAL OPERATOR AND LOCK MEANS THEREFOR FOR OVBRLOAD PROTECTIVE DEVICEOriginal Filed Aug. 20, 1965 '7 Sheets-Sheet 4 1N VENTORS 4 41527- 4/.174411.!-

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MANUAL OPERATOR MID LOCK UBANS THEREFOR FOR OVERLOAD V PROTECTIVE DEVICEv Original Filed Aug. 20, 1965 Sheets-Sheet BY [A 14 f IZIIZ 67204141,19:07 Qwejflnzw 7741 44971 May 7, 1968 R. w. THOMAS ET A 3,332,336

MANUAL OPERATOR AND LOCK MEANS THEREFOR FOR OVERLOAD PROTECTIVE DEVI CEOriginal Filed Aug. 20, 1965 7 Sheets-Sheet 6 (ID (ID ED INVENTORS{415:7 44 77/44/13 BY 1 14/4!) 2' P447! fireman 4, 5162- 5 faea e lip/r4imllfyf May 7, 1968' R. w. THOMAS ET 3,3 ,3

MANUAL OPERATOR AND LOCK MEANS THEREFOR FOR OVERLOAD PROTECTIVE DEVICEOriginal Filed'Aug. 20, 1965 v 7 Sheets-Sheet 2- INVENTORS 05527- za77/0M4S EL. W000 T241972 United States Patent 3,382,336 MANUAL OPERATORAND LOCK MEANS THEREFOR FOR OVERLOAD PROTEC- TIVE DEVICE Robert W.Thomas, St. Clair Shores, and Elwood T. Platz, Grosse Pointe Farms,Mich., assignors to I-T-E Circuit Breaker Company, Philadelphia, Pa., acorporation of Pennsylvania Continuation of application Ser. No.481,235, Aug. 20, 1965, which is a division of application Ser. No.225,044, Sept. 20, 1962. This application Feb. 21, 1967, Ser. No.617,714

11 Claims. (Cl. ZOO-J22) ABSTRACT OF THE DISCLOSURE A manual operatorfor an overload protective device having a thermally actuated overloadsensing bimetallic strip for tripping apart the contacts of the device;the manual operator is elongated with two inclined cam surfaces forminga wide mouthed notch; when the element is depressed: if the contacts aretogether, the first cam surface engages the contact arm of the movablecontact and separates the contacts; or if the contacts are apart, thesecond cam surface engages the contact arm and drives the contactstogether; an alternate form of operator has only the second cam surfaceand has a lock means to retain the element in a depressed position forautomatic reclose.

This is a continuation of application Ser. No. 481,235 filed Aug. 20,1965, which was a division of application Ser. No. 225,044 filed Sept.20, 1962, entitled Overload Relay for Motor Starter. More particularly,this invention relates to a novel arrangement whereby each pole of amulti-pole arrangement is provided with a separate and distinct plug-indevice, with all of the devices connected in electrical series forelectrical coordination. Our novel overload relay device is constructedto be used as an independent piece of apparatus or in conjunction with acontactor to form a motor starter.

Essentially, our invention consists of a plug-in device a unitaryassembly comprised of (a) a heating circuit, (b) a control circuit, (c)an adjustment means, (d) lost motion connector, (e) external control,and an adapter plate to which a plurality of the plug-in devices aremounted.

A. Heater circuit The heater circuit is constructed so that the heaterterminals are readily accessible from the external portion of the casingand the heater, therefore, is readily removable and replaceable withoutdisassembling the casing.

Our device is so constructed so that a variety of heaters can be used,as for example, a U-shaped heater, a coilwound heater, or a two-pieceheater, depending on the electrical requirements of the circuit. Whenthe overload relay is used with a contactor, the arrangement is suchthat one terminal of the heater is electrically connected to the maincontacts of the contactor and the other terminal provides a connectionpreferably to the load terminal.

B. Control circuit Within the same casing containing the heater circuit,a control circuit is located which comprises not only the controlcontacts for the control coil of the contactor, but also the auxiliaryor signal contacts.

Essentially, the control circuit is comprised of a pivoted contact armwhich forms one leg of a toggle and a biasing spring which forms theother leg of the toggle. The conice tact arm is constructed in such amanner that it is pivoted at a central point and carries the maincontacts at one end and the auxiliary or signal contacts at the otherend thereof. The control circuit is further constructed so that theterminals which provide the energization for the main contacts caneither be plug-in terminals or standard screw type terminals. With theplug-in arrangement, the overload relay can be easily mechanically andelectrically connected to a contactor by the simple expedient ofproviding an adapter plate with the contactor.

C. Adjustment device The overload sensing means of our overload relay iscomprised of a bimetal which is mounted on a support means comprised ofa main support and auxiliary support. The auxiliary support is securedin position by a field adjustment means although the main and auxiliarysupport can be moved relative to each other by means of a separate anddistinct factory calibration means. Both the factory calibration meansand the field adjustment means are provided to permit a change in theposition of the bimetal relative to the heater Without distorting thebimetal.

The auxiliary support is constructed as a Z-shaped memher with theconnecting end and particularly the bend at each end being purposelymade weak to permit factory calibration. The bimetal is secured at afirst end and the other end thereof is free to deflect upon heating ofthe bimetal. There is an internal surface of the case which serves as apivot for the assembly of the bimetal, the main support and, theauxiliary support.

D. Lost motion connector As previously noted, the control circuitcomprises a bimetal whose free end can be adjustably positioned and thecontrol circuit comprises a toggle mechanism, one leg of which is abiasing spring. A lost motion translator is provided whereby movement ofthe bimetal away from the heater upon the occurrence of an overloadcurrent is transmitted through the translator to re-position the togglespring so that the toggle is driven over-center thereby resulting in thesimultaneous opening of the main contacts and closing of the auxiliaryor signal contacts. However, as the bimetal cools the toggle spring isnot moved back over center by the translator because of a lost motionarrangement.

E. External control Means are provided in our novel overload relaywhereby a single unit can perform several functions, such as a manualopening operation, a pre-set for automatic re-set operation, a manualre-set of the contacts from the open to the closed position, as well asmanual opening plus lock-off. In essence, there is a plunger deviceprovided with a first and second cam surface. The plunger device can beselectively altered so that with-the first cam surface on the plungerthe device can be manually opened even though the second cam surface ison the plunger. On the other hand, if it is desired to have automaticre-set operation, the first cam surface can be removed from the plungerand the second cam surface will thereby function as an automatic re-setmeans. When the plunger is utilized as a manual opening device, a firstlock-off means can be provided to hold the plunger in the fixed positionand when the plunger is used as an automatic re-set device the samelocking means can be used to hold the plunger in position.

Thus, the plunger is provided with a first and second cam surface withthe first cam surface utilized exclusively for manual opening operationand when the plunger has both a first and second cam surface, the secondcam surface functions as a manual re-set surface. However, when thefirst cam surface is removed, the second cam surface functions both as amanual re-set surface and an automatic re-set surface. It should benoted that the plunger means is removable without dissassembling thehousings so that the first cam surface can readily be removed in thefield, if so desired, without affecting the factory calibration orassembly.

It should be noted that the second cam surface, although in physicalcontact with the contact arm, merely moves the contact arm over centerand does not physically drive the contact arm completely to the engagedposition. That is, the second cam surface merely .re-position'sthetoggle and this permits the spring of the toggle to serve as thequiekclose means for the contact. Hence, the plunger in all positionsthereof will permit a trip-free operation. It should be noted thatundesirable pumping operati n will not result since there is not aninstantaneous trip means. That is, the main contacts will close and willnot be moved to the open position until the bimetal is heated .again butwhen the bimetal is heated, the contacts will be free to move in theopen position until they engage the second cam surface.

F. Adapted plate Means are provided whereby the base of the contactorcan be extended to provide a mechanical support as well as theelectrical connection for a plurality overload relay units. Inparticular, the adapter plate is provided with plug-in contacts andconnecting straps that will automatically connect in all of the maincontacts of the overload relays in electrical series.

The adapter plate is further provided with keying means or a recess toreceive protrusions from the overload relay so that the overload relayplug-in contacts are in alignment with the female contacts of theadapter plate and also to insure that the heater terminal is inalignment with a terminal of the contactor.

Accordingly, a primary object of this invention is to provide a novelconstruction for an overload relay device.

Another object is to provide a novel overload relay of relatively simpleconstruction which possesses reliable operating characteristics.

Still another object is to provide an overload relay having novel meansfor mounting of the bimetal.

A further object is to provide an overload relay having novel means fortripping and lockout.

A still further object is to provide an overload relay having a novelarrangement of the bimetal, motion translator, and toggle switchmechanism.

These and other objects of our invention will be obvious from thefollowing description taken in connection with the drawings, in which:

FIGURE 1 is an exploded perspective showing the heater circuit, controlcircuit and adjustment means of our novel overload relay.

FIGURE 2 is a side view of the overload relay with the cover removed.

FIGURE 2a is a composite side and cross-sectional view similar to FIGURE2 but illustrates the movement of the bimetal, the heater circuit, andthe configuration of the plunger.

FIGURES 341-30 are various and cross-Sectional views of the motorstarter in which FIGURE 30: is taken along line 3a-3a of F IGURE 2alooking in the direction of the arrows 3a3a; FIGURE 3b is taken alongthe line 3b--3b of FIGURE 2w looking in the direction of arrows 3b-3b;and FIGURE 30 is an end view of the device of FIGURE 2 taken from theright end.

FIGURE 4 is a view of the other side of the casing of the overloadrelay.

FIGURE 5 is a top view of the overload relay of FIGURE 2.

FIGURE 60: is an illustration of a two-piece heater that may besubstituted for the U-shaped heater of FIG- URES 1 and 2.

FIGURE 6b is an illustration of a coil ty-pe heater.

FIGURE 6c is a side elevation of a slide utilized for manual tripping ofthe overload relay.

FIGURE is a top view of the adapter plate.

FIGURE 71; is an end view of the adapter plate of FIGURE 7a.

FIGURE 7c is a side view taken in the direction of the arrows 7c--7c ofFIGURE 7a.

FIGURE 7d is a perspective showing the construction of the femaleplug-in contacts.

FIGURE 8 is a composite plan view illustrating the overload relay andadapter plate of our invention in conjunction with a contactor.

FIGURES 9 and 10 are side cross-sections of a part of the relay shown inFIGURE 2 adapted with the slide of FIGURE 6c.

Now referring to the figures and more particularly to FIGURES 1 through5. Overload relay unit 10 consists of a molded housing divided alongline 1 1 to form base 12 and cover 13 joined by screws 75. In a mannerwellknown to the art, base 12 and cover 13 are provided with internaldepressions and protrusions which engage the electrical and activemechanical elements of unit 10 to operatively position these elements.

With respect to FIGURE 2a, there is a top opening 14 which forms anentrance to main cavity 15 in base 12. Disposed externally of housing 10at the top thereof are spaced apart main circuit terminals 16, 17, (asshown in FIGURE 1), each of which are generally L-shaped. A generallyU-shaped resistance heater element '18 is disposed within main cavity 15and is provided with outturned legs 18a at the free ends of the U arms.Out-turned legs 1811 are provided with clearance apertures which receivescrews 19 for securing heater 18 to terminals 16, 17. An auxiliary wireconnector 17a is mounted to extension 17b of terminal 17.

Disposed within cavity 15 and extending generally parallel to one of thelegs of heater 18 is a bi-metallic element 21. The upper end of element21 is fixedly secured as by welding to the upper end of main supportmember 22. Main support 22 extends between the arms 23 at the bifurcatedupper end of auxiliary support 24 and is secured to auxiliary support 24near the free ends of arms 23. The lower ends of supports 22 and 24 arejoined together by factory calibration screw 25 extending through slot26 in auxiliary support 24 and is received in a threaded aperture ofmain support 22. It is noted that arms 23 have two bends therein andthat the crosssectional areas of both arms 23 is less than thecross-sectional area of main support 22. Thus, upon manipulation ofscrew 25 the movement of main support member 22 relative to auxiliarysupport member 24 is accomplished by bending auxiliary support member24.

At a point intermediate its ends, auxiliary support member 24 isprovided with a threaded aperture which receives field adjustment screw27 whose enlarged head 28 is disposed externally of housing 12, 13.Bowed leaf spring 28' is disposed within main cavity 15 with the endsthereof bearing against base 12 and the center portion thereof bearingagainst auxiliary support member 24 at a point thereof near its lowerend. The action of spring 28" urges main support member 22 to seatitself against bearing surface 29 internal of base 12. Surface 29 formsa fixed point of reference about which bimetal 21 moves upon deflectionthereof. Bimetal 21 is so constructed that the lower end thereof is freeto deflect to the right with respect to FIGURE 2 when bimetal 21 isheated.

Bimetal 21, upon deflection thereof, acts through translator bar 31 toseparate movable contact 32 from stationary contact 33 in a manner to behereinafter explained. Stationary contact 33 is mounted to one end ofconducting strap 34 whose other end constitutes plug-in terminal 35extending from the bottom of housing 12, 13. Movable contact 32 ismounted to the upper end of contact arm 36 provided with bifurcatedsections 37 whose free ends are entered into depressions 38 whichconstitute pivot points for movable contact arm 36. Depressions 38 areformed in the upper surfaces of spaced projections 41 extendinghorizontally from conducting strap 39 at a point intermediate the endsthereof. The lower end 40 of strap 39 constitutes a plug-in terminalextending externally of housing 12, 13.

Spring 47 is connected at its lower end to adjustable screw 48 and isconnected at its upper end to contact arm 36. The center line of spring47 extends to the left of the pivot 38 of movable contact arm 36 as seenin FIGURE 2 to thereby exert a force on the movable contact 32 to theleft. However, when the bimetal 21 is heated to cause movement of thetranslator bar 31, the center line of spring 47 is moved to the right ofthe pivot 38 to thereby exert a force on the movable contact to theright as best seen in FIGURE 2(a).

Movable contact arm 36 includes a downwardly extending portion 42positioned between arms 37 and extending between projections 41. Spring47 is secured to the inner end of adjusting screw 48. Screw 48 isthreadably mounted to conducting strap 39. Base 12 is provided withaperture 49 through which the slotted end of screw 48 is accessible foradjustment. The position of screw 48 positions the lower end of spring47 thereby determining the point at which contacts 32, 33 will part asspring 47 is moved to the right by translator bar 31 upon heating ofbimetal 21.

Slidably mounted within a suitable guideway of members 12 is reset slide50. The down-turned end 51 of V-shaped spring 52 extends into housingwindow 73 and is received in side notch 53 of slide 50 while the otherend 54 of spring 52 bears against an external surface of base 12. Theapex of spring 52 is disposed below the head of screw 55 which securesspring 52 to base 12. Spring 52 is partially loaded in a direction suchthat the arms thereof are urged to separate thereby urging slide 50 toits outward position illustrated in FIGURE 2. In this position inclinedreset surface 57 at the lower end of slide 50 is so positioned that whentranslator bar 31 moves the spring 47 sufficiently to the right ofnotches 38, with respect to FIGURE 2, movable contact 32 separates fromstationary contact 33 by a sufficient distance so that upon cooling ofbimetal 21 contacts 32, 33 will not automatically close.

With contacts 32, 33 separated, after reset slide 50 is moved downwardwith respect to FIGURE 2, surface 57 engages the upper end of contactarm 36 driving movable contact arm 36 over center to the left so thatspring 47 is effective to move contact 32 into engagement with contact33.

For automatic resetting, slide 50 is moved inward to a position wherenotch 61 is in line with locking member 58. Thereafter member 58 ismoved to the left with respect to FIGURE 2 into notch 61. Locking screw62, extending through elongated slot 58a of member 58, maintains member58 in adjusted position.

Factory calibration for bimetal 21 is achieved by manipulating screw 25.As screw 25 is adjusted main support 22 and bimetal 21 are bodily movedas a unit. During this period of time auxiliary support 24 isessentially stationary although the upper portion thereof deforms topermit the aforesaid movement of main support 22. Field adjustment knob28 is operated to rotate screw 27. This movement brings about the bodilymovement of auxiliary support 24, main support 22 and bimetal 21 as aunit with bearing surface 29 acting as a pivot. It is noted that knob 28is provided with a radial projection 63 which cooperates with base stop64 to limit rotation of screw 27 to approximately one revolution.

It is noted that device as hereinbefore described does not provide formanual tripping. Such provisions may readily be provided by removingreset slide 50 and replacing same by tripping slide 500. Slide 500 (FIG-URES 6c, 9 and 10) contains all of the features of slide 50 and inaddition contains a portion 70 at its lower end including tripping camsurface 71. It is noted that portion 70 is connected to the remainder ofslide 50a at a weakened section 72 which defines a fracture line so thatportion 70 can be broken away should it be desired to eliminate themanual tripping feature.

Slide 501: may be substituted for slide 50 merely by removing spring tip51 from notch 53 thereby permitting slide 50 to be moved upward out ofhousing 12, 13. Thereafter slide 5012; is inserted and is maintained inoperative position by placing spring tip 51 into notch 53a whe e latterbecomes viewable at base window 73.

Referring to FIGURE 9, with contacts 32, 33 in closed position, downwardmovement of slide 50a from the fully projected position brings trippingcam surface 71 into engagement with movable contact arm 36 moving thelatter clockwise, as viewed in FIGURE 9, about pivot depressions 38 toseparate contact 32 from contact 33. Upon subsequent release of slide50a spring 52 moves slide 50a upward thereby permitting spring 47 tomove contact 32 back into engagement with contact 33.

Referring to FIGURE 10, should contacts 32, 33 be separated through thedeflection of bimetal 21, those contacts may be brought back intoengagement after cooling of bimetal 21 by depressing slide 50a. Thismovement of slide 50a bringscam surface 57a into engagement with theupper end of movable contact arm 36 moving the latter counterclockwise,as viewed in FIGURE 10 to a position where the toggle is over center tothe left thereby permi.ting spring 47 to drive movable contact arm 36into engagement with tripping cam surface 71 and upon release of slide5011 movable contact 32 will engage stationary contact 33.

In order to maintain contacts 32, 33 disengaged, as during a period whenrelated equipment is being serviced, slide 50a may be maintained in itsinward position by moving locking member 58 to the left, with respect toFIGURE 9, into slot 61a at the edge of manual tripping slide 50a.

In the device hereinbefore described, the bimetal heater consists of asingle piece U-shaped resistance element 18. Element 18 may readily bereplaced without removing screw 75 which secures cover 13 to base 12.That is, it is merely necessary to remove screws 19 from terminals 16,17 and thereafter move heater 18 upward with respect to FIGURE 2.

Heater 18 may be replaced by either of the heater constructionsillustrated in FIGURES 6a or 6b. The heater assembly of FIGURE 6acomprises copper conducting strap 101 whose out-turned end 102 isadapted to abut terminal 16. Heater asesmbly 100 also includesresistance leg 103 extending generally parallel to leg 101 and spacedtherefrom. The outwardly turned end 104 of leg 103 is adapted to abutterminal 17. Legs 101 and 103 are combined as by welding at 105. Inheater assembly 100, heating is concentrated in leg 103 which ispositioned closer to bimetal 21 than is leg 101. For some applicationsbimetal 21 appears to be more sensitive to heat generated by heater 100than by heater 18.

FIGURE 6b illustrates a heater in the form of resistance wire which isspiraled about insulating support in two layers. The eyelet conectedends 111, 112 of coil 110 are adapted to be connected to terminals 16and 17 by means of screws 19.

With contacts 32, 33 in engagement a complete electrical path existsbetween plug-in terminals 35 and 40. This path comprises terminal 35,conducting strap 34 to stationary contact 33, movable contact 32,movable contact arm 36, and conducting strap 39 to terminal 40. Thisseries circuit is intended to be connected in series with the operatingcoil for contactor 200 as shown in FIGURE 8.

With reset slide 50 or tripping slide 50a in the fully extended positionand contacts 32, 33 disengaged, contacts 43, 44 will be in engagement.This completes a series circuit extending from terminal 40 throughconducting strap 39, movable contact arm 36, extension 42, movablecontact 43 through stationary contact 44, and strap 45 to terminalmember 46. The last noted circuit is used for signalling purposes toindicate when unit has been tripped open and must be manually reset.

Overload relay units of the type described are usually in conjunctionwith contactors for controlling the energization of motors. Thiscombination is effectively achieved by providing plug-in base 150 asillustrated in FIGURE 7a-7d. When used in cnjunction with a three phasecontactor 200, plug-in base 150 comprises three pairs of spaced contactreceiving jaws 151a, 151b; 1520, 1521:; 153a, 1531). These contactreceiving jaws are mounted to the main portion 155 of plug-in base 150which is also provided with a plurality of locating apertures 151s,152s, and 153c in alignment with the respective pairs of contactreceiving jaws. Plug-in base 150 is also provided with an end portion156 which extends at right angles to main portion 155 and is stepped toprovide seats for terminals 157, 158.

Depressions 151e, 1520 and 1530 are adapted to receive a projection 159extending downwardly from the bottom of base 12 for positioning unit 10.With projection 159 of unit 10 disposed within depression 1510 contactjaws 151a engage contact 40 and contact jaws 151b engage contact 35.Similar units 10 are mounted in the plug-inbase 150 at locations definedby depressions 152a and 153s.

Disposed within plug-in base 150 are conductors for establishing aseries circuit from terminal 157 to terminal 158 when three closedoverload relay units 10 are mounted to base 150. Thus, conductor 165extends from terminal 157 to jaws 153b, conductor 166 extends from jaws153a to jaws 152b, Conductor 167 extends from jaws 152a to jaws 151b,and conductor 168 extends from jaws 151a to terminal 158. As seen inFIGURE 7:! jaws are formed on both ends of conductor 166 and formedintegrally therewith. For a situation where only the outer locationsdefined by depressions 151a and 153s are to be utilized a strap isplaced between jaws 153a and jaws 151b.

With plug-in base 150 properly mounted at one end of contactor 200, whenan overload relay unit 10 is mounted to base 150 this unit 10 isautomatically positioned with the upturned portion 16a of its mainterminal 16 abutting a main contact terminal 201 of contactor 200'.

Although there has been described a preferred embodiment of this novelinvention, many variations and modifications will now be apparent tothose skilled in the art. Therefore, this invention is to be limited,not by the specific disclosure herein, but only by the appending claims.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

1. An overload protective device comprising, a pair of cooperatingcontacts, an overcenter toggle for operating one of said contacts intoand out of engagement with the other of said contacts; said toggleincluding a contact arm to which is mounted said one contact of saidpair of contacts;

an operating mechanism comprising, a first cam having a first camsurface means; a second cam having a second cam surface means; and amanually operable member for operating said first and said second camsin a first direction; said first and said second cams being connected tosaid manually operable member so as to be simultaneously movable therebyin the first direction;

said first cam surface means operating into engagement with said contactarm when said pair of contacts is engaged for moving said one contactout of engagement with said other contact; said first cam surface meansbeing shaped and positioned to slidably engage said contact arm; wherebyfirst actuation of said manually operable member in said first directionmoves said one contact out of engagement with said other contact;

said second cam surface means operating into engagement with saidcontact arm when said pair of contacts is disengaged for moving said onecontact toward said other contact and toward the apex of a notch formedby said first and said second cam surfaces; said second cam surfacemeans being shaped and positioned to slidably engage said contact arm;whereby second actuation of said manually operable member in said firstdirection moves said one contact toward said other contact;

said first and said second cam surface means forming .a tapered widemouthed notch having an apex;

said first and said second cam surface means being shaped for movingsaid contact arm toward said apex of said notch when said manuallyoperable member is actuated in the first direction.

2. The overload protective device of claim 1, comprising a biasing meansconnected with said manually operable member for normally biasing saidmanually operable member in a second direction opposite said firstdirection.

3. The overload protective device of claim 1, wherein said notch is sopositioned that when said manually operable member has been actuated inthe first direction so that said contact arm is at the apex of saidnotch, said toggle is positioned overcenter in a direction which permitsclosing of said cooperating contacts by means of said toggle when saidmanually operable member is moved in a direction opposite said firstdirection.

4. The overload protective device of claim 1 further comprising,

' a tripping device comprising a bimetallic strip heated by a circuitbeing protected; said contacts being in the circuit being protected;said strip being connected with said toggle, whereby when said strip isheated by an overload condition in the circuit, said strip causes saidtoggle to operate said one contact out of engagement with the other saidcontact.

5. The overload protective device of claim 1, wherein said operatingmechanism is removable and replaceable with a second operating mechanismcomprising,

a third cam having a third cam surface means and a second manuallyoperable member for operating said third cam in the first direction;said third cam being connected to said second manually operable member;said third cam operating into engagement with said contact arm when saidpair of contacts is disengaged for moving said one contact toward theother contact of said pair of contacts; whereby third actuation of saidsecond manually operable member in said 'first direction moves said onecontact toward said other contact.

6. The overload protective device of claim 5, further comprising,

a housing containing said contacts and said toggle;

a lock means for said second manually operable member; said secondmanually operable member having a means for receiving said lock means,which receiving means is positioned on said second manually operablemember to receive said lock means after said second manually operablemember has been actuated in the first direction a predetermineddistance;

said lock means being mounted to said housing and being movable withrespect thereto into said receiving means of said second manuallyoperable member;

a tripping device comprising a bimetallic strip heated by a circuitbeing protected; said contacts being in the circuit being protected;said strip being connected with said toggles whereby when said strip isheated by an overload condition in the circuit, said strip causes saidtoggle to operate said one contact out of engagement with the other saidcontact.

7. An overload protective device comprising,

a housing, a pair of cooperating contacts within said housing, anovercenter toggle within said housing for operating one of said contactsinto and out of engagement with the other of said contacts; said toggleincluding a contact arm to which is mounted said one contact of saidpair of contacts; 1

a tripping device comprising a bimetallic strip heated by a circuitbeing protected; said contacts being in the circuit being protected;said strip being connected with said toggles whereby when said strip isheated by an overload condition in the circuit said strip causes saidtoggle to operate said one contact out of engagement with the other saidcontact;

an operating mechanism,

said operating mechanism comprising a cam having a cam surface means anda manually operable member for operating said cam in the firstdirection; said cam being connected to said manually operable member;said cam operating into engagement with said contact arm when said pairof contacts is disengaged for moving said one contact toward the othercontact of said pair of contacts; whereby first actuation of saidmanually operable member in said first direction moves said one contacttoward said other contact;

a lock means for said manually operable member; said manually operablemember having a means for receiving said lock means, which receivingmeans is positioned on said manually operable member to receive saidlock means after said manually operable member has been actuated in thefirst direction a predetermined distance;

said lock means being mounted to said housing and being movable withrespect thereto into said receiving means of said manually operablemember.

8. The overload protective device of claim 7, wherein said lock means isaccessible from without said housing to enable said lock means to bemoved.

9. The overload protective device of claim 7, wherein said receivingmeans comprises a notch in said manually operable member; said notchbeing transverse to said first direction.

10. The overload protective device of claim 7, wherein said cam surfacemeans is shaped and positioned to slidably engage said contact arm.

11. The overload protective device of claim 7, wherein said operatingmechanism is removable and replaceable with a second operating mechanismcomprising,

a second cam having a second cam surface means, a third cam having athird cam surface means; and a second manually operable member foroperating said second and third cams in the first direction; said 5second and third cams being connected to said second manually operablemember so as to be simultaneously movable thereby in the firstdirection; said second cam surface means operating into engagement withsaid contact arm when said pair of contacts is engaged for moving saidone contact out of engagement with said other contact; said second camsurface means being shaped and positioned to slidably engage saidcontact arm; whereby second actuation of said manually operable memberin said first direction moves said one contact out of engagement withsaid other contact; said third cam surface operating into engagementwith said contact arm when said pair of contacts is disengaged formoving said one contact toward said other contact and toward the apex ofa notch formed by said second and said third cam surface means; saidthird cam surface means being shaped and positioned to slidably engagesaid contact arm; whereby third actuation of said second manuallyoperable member in said first direction moves said one contact towardsaid other contact; said second and said third cam surface means beingarranged to form a tapered wide-mounted notch having an apex; saidsecond and said third cam surface means being so shaped that saidcontact arm is moved toward said apex of said notch when said manuallyoperable member is actuated in the first direction.

References Cited UNITED STATES PATENTS 5 BERNARD A. GILHEANY, PrimaryExaminer.

H. A. LEWITI'ER, R. COHRS, Assistant Examiners.

